enable more GCC/clang warnings, fix reported warnings

CMakeLists.txt

@@ -564,7 +564,7 @@ SET (RECVFROM_TYPE_ARG5 "struct sockaddr *")
 SET (RECV_TYPE_ARG4 int)
 SET (GETNAMEINFO_TYPE_ARG1 "struct sockaddr *")
 SET (GETNAMEINFO_TYPE_ARG7 int)
-SET (SEND_TYPE_ARG2 "void *")
+SET (SEND_TYPE_ARG2 "const void *")
 SET (SEND_TYPE_ARG4 int)
 ################################################################################
 

Makefile.dj

@@ -21,9 +21,12 @@ OBJ_DIR = djgpp
 
 CFLAGS = -g -O2 -I./include -I./src/lib \
          -I$(WATT32_ROOT)/inc \
+         -std=c90 \
          -Wall \
          -Wextra \
+         -Waggregate-return \
          -Wcast-align \
+         -Wcast-qual \
          -Wconversion \
          -Wdeclaration-after-statement \
          -Wdouble-promotion \
@@ -40,6 +43,7 @@ CFLAGS = -g -O2 -I./include -I./src/lib \
          -Wno-coverage-mismatch \
          -Wold-style-definition \
          -Wpacked \
+         -Wpedantic \
          -Wpointer-arith \
          -Wshadow \
          -Wsign-conversion \
@@ -47,12 +51,14 @@ CFLAGS = -g -O2 -I./include -I./src/lib \
          -Wstrict-prototypes \
          -Wtrampolines \
          -Wundef \
+         -Wunreachable-code \
          -Wunused \
          -Wvariadic-macros \
          -Wvla \
          -Wwrite-strings \
          -Werror=implicit-int \
          -Werror=implicit-function-declaration \
+         -Wno-long-long \
          -DWATT32 -DHAVE_CONFIG_H   \
          -D_REENTRANT \
          -DCARES_NO_DEPRECATED \

cmake/EnableWarnings.cmake

@@ -305,7 +305,9 @@ else ()
 		-Wextra
 
 		# Enable additional warnings not covered by Wall and Wextra.
+		-Waggregate-return
 		-Wcast-align
+		-Wcast-qual
 		-Wconversion
 		-Wdeclaration-after-statement
 		-Wdouble-promotion
@@ -323,6 +325,7 @@ else ()
 		-Wno-coverage-mismatch
 		-Wold-style-definition
 		-Wpacked
+		-Wpedantic
 		-Wpointer-arith
 		-Wredundant-decls
 		-Wshadow
@@ -331,6 +334,7 @@ else ()
 		-Wstrict-prototypes
 		-Wtrampolines
 		-Wundef
+		-Wunreachable-code
 		-Wunused
 		-Wvariadic-macros
 		-Wvla
@@ -349,6 +353,8 @@ else ()
 		# Some clang versions might warn if an argument like "-I/path/to/headers" is unused,
 		# silence these.
 		-Qunused-arguments
+
+		-Wno-long-long
 	)
 
 	# C++ flags:

configure.ac

@@ -245,42 +245,8 @@ AC_SUBST(CARES_SYMBOL_HIDING_CFLAG)
 
 
 if test "$enable_warnings" = "yes"; then
-  AX_APPEND_COMPILE_FLAGS([-Wall \
+  AX_APPEND_COMPILE_FLAGS([-std=c90 -Wall -Wextra -Waggregate-return -Wcast-align -Wcast-qual -Wconversion -Wdeclaration-after-statement -Wdouble-promotion -Wfloat-equal -Wformat-security -Winit-self -Wjump-misses-init -Wlogical-op -Wmissing-braces -Wmissing-declarations -Wmissing-format-attribute -Wmissing-include-dirs -Wmissing-prototypes -Wnested-externs -Wno-coverage-mismatch -Wold-style-definition -Wpacked -Wpedantic -Wpointer-arith -Wredundant-decls -Wshadow -Wsign-conversion -Wstrict-overflow -Wstrict-prototypes -Wtrampolines -Wundef -Wunreachable-code -Wunused -Wvariadic-macros -Wvla -Wwrite-strings -Werror=implicit-int -Werror=implicit-function-declaration -Werror=partial-availability -Wno-long-long ],
-    -Wextra \
+    [AM_CFLAGS], [-Werror])
-    -Wcast-align \
-    -Wconversion \
-    -Wdeclaration-after-statement \
-    -Wdouble-promotion \
-    -Wfloat-equal \
-    -Wformat-security \
-    -Winit-self \
-    -Wjump-misses-init \
-    -Wlogical-op \
-    -Wmissing-braces \
-    -Wmissing-declarations \
-    -Wmissing-format-attribute \
-    -Wmissing-include-dirs \
-    -Wmissing-prototypes \
-    -Wnested-externs \
-    -Wno-coverage-mismatch \
-    -Wold-style-definition \
-    -Wpacked \
-    -Wpointer-arith \
-    -Wredundant-decls \
-    -Wshadow \
-    -Wsign-conversion \
-    -Wstrict-overflow \
-    -Wstrict-prototypes \
-    -Wtrampolines \
-    -Wundef \
-    -Wunused \
-    -Wvariadic-macros \
-    -Wvla \
-    -Wwrite-strings \
-    -Werror=implicit-int \
-    -Werror=implicit-function-declaration \
-    -Werror=partial-availability \
-  ], [AM_CFLAGS], [-Werror])
 fi
 
 if test "$ax_cv_c_compiler_vendor" = "intel"; then
@@ -663,7 +629,7 @@ recvfrom_type_arg5="struct sockaddr *"
 recv_type_arg4=int
 getnameinfo_type_arg1="struct sockaddr *"
 getnameinfo_type_arg7=int
-send_type_arg2="void *"
+send_type_arg2="const void *"
 send_type_arg4=int
 
 AC_DEFINE_UNQUOTED([RECVFROM_TYPE_RETV],     [ ${recvfrom_type_retv} ],     [ recvfrom() return value ])

include/ares_dns_record.h

@@ -94,7 +94,7 @@ typedef enum {
   ARES_OPCODE_IQUERY = 1, /*!< Inverse query. Obsolete. */
   ARES_OPCODE_STATUS = 2, /*!< Name server status query */
   ARES_OPCODE_NOTIFY = 4, /*!< Zone change notification (RFC 1996) */
-  ARES_OPCODE_UPDATE = 5, /*!< Zone update message (RFC2136) */
+  ARES_OPCODE_UPDATE = 5  /*!< Zone update message (RFC2136) */
 } ares_dns_opcode_t;
 
 /*! DNS Header flags */
@@ -108,7 +108,7 @@ typedef enum {
   ARES_FLAG_AD = 1 << 5, /*!< RFC 2065. Authentic Data bit indicates in a
                           * response that the data included has been verified by
                           * the server providing it */
-  ARES_FLAG_CD = 1 << 6, /*!< RFC 2065. Checking Disabled bit indicates in a
+  ARES_FLAG_CD = 1 << 6  /*!< RFC 2065. Checking Disabled bit indicates in a
                           * query that non-verified data is acceptable to the
                           * resolver sending the query. */
 } ares_dns_flags_t;
@@ -152,7 +152,7 @@ typedef enum {
   ARES_RCODE_BADNAME   = 20, /*!< RFC 2930. Duplicate Key Name */
   ARES_RCODE_BADALG    = 21, /*!< RFC 2930. Algorithm not supported */
   ARES_RCODE_BADTRUNC  = 22, /*!< RFC 8945. Bad Truncation */
-  ARES_RCODE_BADCOOKIE = 23, /*!< RVC 7973. Bad/missing Server Cookie */
+  ARES_RCODE_BADCOOKIE = 23  /*!< RVC 7973. Bad/missing Server Cookie */
 } ares_dns_rcode_t;
 
 /*! Data types used */
@@ -169,7 +169,7 @@ typedef enum {
                               *   printable. Guaranteed to have a NULL
                               *   terminator for convenience (not included in
                               *   length) */
-  ARES_DATATYPE_OPT = 10,    /*!< Array of options.  16bit identifier, BIN
+  ARES_DATATYPE_OPT = 10     /*!< Array of options.  16bit identifier, BIN
                               *   data. */
 } ares_dns_datatype_t;
 
@@ -292,7 +292,7 @@ typedef enum {
   /*! RAW Record. RR Type. Datatype: U16 */
   ARES_RR_RAW_RR_TYPE = (ARES_REC_TYPE_RAW_RR * 100) + 1,
   /*! RAW Record. RR Data. Datatype: BIN */
-  ARES_RR_RAW_RR_DATA = (ARES_REC_TYPE_RAW_RR * 100) + 2,
+  ARES_RR_RAW_RR_DATA = (ARES_REC_TYPE_RAW_RR * 100) + 2
 } ares_dns_rr_key_t;
 
 /*! TLSA Record ARES_RR_TLSA_CERT_USAGE known values */
@@ -372,7 +372,7 @@ typedef enum {
   /*! RFC 8145. Signaling Trust Anchor Knowledge in DNSSEC */
   ARES_OPT_PARAM_EDNS_KEY_TAG = 14,
   /*! RFC 8914. Extended ERROR code and message */
-  ARES_OPT_PARAM_EXTENDED_DNS_ERROR = 15,
+  ARES_OPT_PARAM_EXTENDED_DNS_ERROR = 15
 } ares_opt_param_t;
 
 /*! Data type for option records for keys like ARES_RR_OPT_OPTIONS and

src/lib/ares__addrinfo2hostent.c

@@ -165,13 +165,13 @@ ares_status_t ares__addrinfo2hostent(const struct ares_addrinfo *ai, int family,
       if (family == AF_INET6) {
         memcpy(
           (*host)->h_addr_list[i],
-          &(CARES_INADDR_CAST(struct sockaddr_in6 *, next->ai_addr)->sin6_addr),
+          &(CARES_INADDR_CAST(const struct sockaddr_in6 *, next->ai_addr)->sin6_addr),
           (size_t)(*host)->h_length);
       }
       if (family == AF_INET) {
         memcpy(
           (*host)->h_addr_list[i],
-          &(CARES_INADDR_CAST(struct sockaddr_in *, next->ai_addr)->sin_addr),
+          &(CARES_INADDR_CAST(const struct sockaddr_in *, next->ai_addr)->sin_addr),
           (size_t)(*host)->h_length);
       }
       ++i;
@@ -256,7 +256,7 @@ ares_status_t ares__addrinfo2addrttl(const struct ares_addrinfo *ai, int family,
 
       memcpy(
         &addr6ttls[*naddrttls].ip6addr,
-        &(CARES_INADDR_CAST(struct sockaddr_in6 *, next->ai_addr)->sin6_addr),
+        &(CARES_INADDR_CAST(const struct sockaddr_in6 *, next->ai_addr)->sin6_addr),
         sizeof(struct ares_in6_addr));
     } else {
       if (next->ai_ttl > cname_ttl) {
@@ -266,7 +266,7 @@ ares_status_t ares__addrinfo2addrttl(const struct ares_addrinfo *ai, int family,
       }
       memcpy(
         &addrttls[*naddrttls].ipaddr,
-        &(CARES_INADDR_CAST(struct sockaddr_in *, next->ai_addr)->sin_addr),
+        &(CARES_INADDR_CAST(const struct sockaddr_in *, next->ai_addr)->sin_addr),
         sizeof(struct in_addr));
     }
     (*naddrttls)++;

src/lib/ares_event_configchg.c

@@ -473,7 +473,7 @@ ares_status_t ares_event_configchg_init(ares_event_configchg_t **configchg,
       continue;
     }
 
-    pdns_configuration_notify_key =
+    pdns_configuration_notify_key = (const char *(*)(void))
       dlsym(handle, "dns_configuration_notify_key");
     if (pdns_configuration_notify_key != NULL) {
       break;

src/lib/ares_gethostbyname.c

@@ -102,13 +102,17 @@ static void ares_gethostbyname_callback(void *arg, int status, int timeouts,
 void ares_gethostbyname(ares_channel_t *channel, const char *name, int family,
                         ares_host_callback callback, void *arg)
 {
-  const struct ares_addrinfo_hints hints = { ARES_AI_CANONNAME, family, 0, 0 };
+  struct ares_addrinfo_hints hints;
-  struct host_query               *ghbn_arg;
+  struct host_query         *ghbn_arg;
 
   if (!callback) {
     return;
   }
 
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_flags  = ARES_AI_CANONNAME;
+  hints.ai_family = family;
+
   ghbn_arg = ares_malloc(sizeof(*ghbn_arg));
   if (!ghbn_arg) {
     callback(arg, ARES_ENOMEM, 0, NULL);

src/lib/ares_getnameinfo.c

@@ -100,11 +100,11 @@ static void  ares_getnameinfo_int(ares_channel_t        *channel,
   /* Validate socket address family and length */
   if (sa && sa->sa_family == AF_INET &&
       salen >= (ares_socklen_t)sizeof(struct sockaddr_in)) {
-    addr = CARES_INADDR_CAST(struct sockaddr_in *, sa);
+    addr = CARES_INADDR_CAST(const struct sockaddr_in *, sa);
     port = addr->sin_port;
   } else if (sa && sa->sa_family == AF_INET6 &&
              salen >= (ares_socklen_t)sizeof(struct sockaddr_in6)) {
-    addr6 = CARES_INADDR_CAST(struct sockaddr_in6 *, sa);
+    addr6 = CARES_INADDR_CAST(const struct sockaddr_in6 *, sa);
     port  = addr6->sin6_port;
   } else {
     callback(arg, ARES_ENOTIMP, 0, NULL, NULL);

src/lib/ares_private.h

@@ -41,7 +41,7 @@
  * warning: cast from 'const struct sockaddr *' to 'const struct sockaddr_in6 *'
  * increases required alignment from 1 to 4 [-Wcast-align]
  */
-#define CARES_INADDR_CAST(type, var) ((type)((void *)var))
+#define CARES_INADDR_CAST(type, var) ((type)((const void *)var))
 
 #if defined(USE_WINSOCK)
 

src/lib/ares_process.c

@@ -1222,14 +1222,14 @@ static ares_bool_t same_address(const struct sockaddr  *sa,
     switch (aa->family) {
       case AF_INET:
         addr1 = &aa->addr.addr4;
-        addr2 = &(CARES_INADDR_CAST(struct sockaddr_in *, sa))->sin_addr;
+        addr2 = &(CARES_INADDR_CAST(const struct sockaddr_in *, sa))->sin_addr;
         if (memcmp(addr1, addr2, sizeof(aa->addr.addr4)) == 0) {
           return ARES_TRUE; /* match */
         }
         break;
       case AF_INET6:
         addr1 = &aa->addr.addr6;
-        addr2 = &(CARES_INADDR_CAST(struct sockaddr_in6 *, sa))->sin6_addr;
+        addr2 = &(CARES_INADDR_CAST(const struct sockaddr_in6 *, sa))->sin6_addr;
         if (memcmp(addr1, addr2, sizeof(aa->addr.addr6)) == 0) {
           return ARES_TRUE; /* match */
         }

src/lib/ares_rand.c

@@ -43,7 +43,7 @@
 typedef enum {
   ARES_RAND_OS   = 1 << 0, /* OS-provided such as RtlGenRandom or arc4random */
   ARES_RAND_FILE = 1 << 1, /* OS file-backed random number generator */
-  ARES_RAND_RC4  = 1 << 2, /* Internal RC4 based PRNG */
+  ARES_RAND_RC4  = 1 << 2  /* Internal RC4 based PRNG */
 } ares_rand_backend;
 
 #define ARES_RC4_KEY_LEN 32 /* 256 bits */

src/lib/ares_sysconfig_mac.c

@@ -45,6 +45,11 @@
  * private header extracted from:
  * https://opensource.apple.com/source/configd/configd-1109.140.1/dnsinfo/dnsinfo.h
  */
+
+/* The apple header uses anonymous unions which came with C11 */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wc11-extensions"
+
 #  include "ares_setup.h"
 #  include <stdio.h>
 #  include <stdlib.h>
@@ -110,10 +115,10 @@ static ares_status_t dnsinfo_init(dnsinfo_t **dnsinfo_out)
       continue;
     }
 
-    dnsinfo->dns_configuration_copy =
+    dnsinfo->dns_configuration_copy = (dns_config_t *(*)(void))
       dlsym(dnsinfo->handle, "dns_configuration_copy");
 
-    dnsinfo->dns_configuration_free =
+    dnsinfo->dns_configuration_free = (void (*)(dns_config_t *))
       dlsym(dnsinfo->handle, "dns_configuration_free");
 
     if (dnsinfo->dns_configuration_copy != NULL &&
@@ -365,6 +370,7 @@ done:
   }
   return status;
 }
+#pragma GCC diagnostic pop
 
 
 #endif

src/tools/adig.c

@@ -113,12 +113,16 @@ static void free_config(adig_config_t *config)
 
 static void print_help(void)
 {
+  /* Split due to maximum c89 string literal of 509 bytes */
   printf("adig version %s\n\n", ares_version(NULL));
   printf(
     "usage: adig [-h] [-d] [-f flag] [[-s server] ...] [-T|U port] [-c class]\n"
-    "            [-t type] name ...\n\n"
+    "            [-t type] name ...\n\n");
-    "  -h : Display this help and exit.\n"
+  printf(
-    "  -d : Print some extra debugging output.\n"
+    "  -h : Display this help and exit.\n");
+  printf(
+    "  -d : Print some extra debugging output.\n");
+  printf(
     "  -f flag   : Add a behavior control flag. Possible values are\n"
     "              igntc     - do not retry a truncated query as TCP, just\n"
     "                          return the truncated answer\n"
@@ -127,21 +131,26 @@ static void print_help(void)
     "              norecurse - don't query upstream servers recursively\n"
     "              primary   - use the first server\n"
     "              stayopen  - don't close the communication sockets\n"
-    "              usevc     - use TCP only\n"
+    "              usevc     - use TCP only\n");
+  printf(
     "  -s server : Connect to the specified DNS server, instead of the\n"
     "              system's default one(s). Servers are tried in round-robin,\n"
-    "              if the previous one failed.\n"
+    "              if the previous one failed.\n");
-    "  -T port   : Connect to the specified TCP port of DNS server.\n"
+  printf(
-    "  -U port   : Connect to the specified UDP port of DNS server.\n"
+    "  -T port   : Connect to the specified TCP port of DNS server.\n");
+  printf(
+    "  -U port   : Connect to the specified UDP port of DNS server.\n");
+  printf(
     "  -c class  : Set the query class. Possible values for class are:\n"
-    "              ANY, CHAOS, HS and IN (default)\n"
+    "              ANY, CHAOS, HS and IN (default)\n");
+  printf(
     "  -t type   : Query records of the specified type. Possible values for\n"
     "              type are:\n"
     "              A (default), AAAA, ANY, CNAME, HINFO, MX, NAPTR, NS, PTR,\n"
     "              SOA, SRV, TXT, TLSA, URI, CAA, SVCB, HTTPS\n\n");
 }
 
-static ares_bool_t read_cmdline(int argc, const char **argv,
+static ares_bool_t read_cmdline(int argc, const char * const * argv,
                                 adig_config_t *config)
 {
   ares_getopt_state_t state;
@@ -897,7 +906,7 @@ int main(int argc, char **argv)
   memset(&config, 0, sizeof(config));
   config.qclass = ARES_CLASS_IN;
   config.qtype  = ARES_REC_TYPE_A;
-  if (!read_cmdline(argc, (const char **)argv, &config)) {
+  if (!read_cmdline(argc, (const char * const *)argv, &config)) {
     printf("\n** ERROR: %s\n\n", config.error);
     print_help();
     rv = 1;

src/tools/ahost.c

@@ -95,7 +95,7 @@ int         main(int argc, char **argv)
     return 1;
   }
 
-  ares_getopt_init(&state, argc, (const char **)argv);
+  ares_getopt_init(&state, argc, (const char * const *)argv);
   while ((c = ares_getopt(&state, "dt:h?D:s:")) != -1) {
     switch (c) {
       case 'd':
@@ -276,18 +276,22 @@ static void usage(void)
 /* Information from the man page. Formatting taken from man -h */
 static void print_help_info_ahost(void)
 {
+  /* Split due to maximum c89 string literal of 509 bytes */
   printf("ahost, version %s\n\n", ARES_VERSION_STR);
   printf(
     "usage: ahost [-h] [-d] [-D domain] [-s server] [-t a|aaaa|u] host|addr "
-    "...\n\n"
+    "...\n\n");
+  printf(
     "  -h : Display this help and exit.\n"
     "  -d : Print some extra debugging output.\n\n"
     "  -D domain : Specify the domain to search instead of using the default "
-    "values\n"
+    "values\n");
+  printf(
     "  -s server : Connect to the specified DNS server, instead of the\n"
     "              system's default one(s). Servers are tried in round-robin,\n"
     "              if the previous one failed.\n"
-    "  -t type   : If type is \"a\", print the A record.\n"
+    "  -t type   : If type is \"a\", print the A record.\n");
+  printf(
     "              If type is \"aaaa\", print the AAAA record.\n"
     "              If type is \"u\" (default), print both A and AAAA records.\n"
     "\n");

src/tools/ares_getopt.c

@@ -47,9 +47,9 @@
 
 #define BADCH  (int)'?'
 #define BADARG (int)':'
-#define EMSG   (char *)""
+#define EMSG   ""
 
-void ares_getopt_init(ares_getopt_state_t *state, int nargc, const char **nargv)
+void ares_getopt_init(ares_getopt_state_t *state, int nargc, const char * const * nargv)
 {
   memset(state, 0, sizeof(*state));
   state->opterr = 1;

src/tools/ares_getopt.h

@@ -40,10 +40,10 @@ typedef struct {
   int          optopt; /* character checked for validity */
   const char  *place;
   int          argc;
-  const char **argv;
+  const char * const *argv;
 } ares_getopt_state_t;
 
-void ares_getopt_init(ares_getopt_state_t *state, int argc, const char **argv);
+void ares_getopt_init(ares_getopt_state_t *state, int argc, const char * const * argv);
 int  ares_getopt(ares_getopt_state_t *state, const char *ostr);
 
 #endif /* ARES_GETOPT_H */